关键词: 砂岩蠕变, 单轴压缩蠕变, 含水率, 径向应变, 长期强度

Abstract: To study the long-term creep mechanical properties of surrounding rock in the deep roadway under the action of groundwater, a self-developed five-joint rheological experimental system was used to carry out uniaxial compression tests and uniaxial creep tests on sandstone with different water contents (0%, 0.8%, 1.6%, 2.4%, and 3.3%) under water absorption and softening conditions. Some experimental findings were revealed. The uniaxial compressive strength, elastic modulus, and creep failure stress of sandstone decrease exponentially with water content, and the ratio of creep failure stress to uniaxial compressive strength ranges from 0.76 to 0.84. The attenuation creep time of sandstone decreases with the increase of water content and increases with the increase of stress level. The radial strain enters the steady-state creep stage earlier than the axial strain, and the accelerated creep stage of the radial strain under the damage stress starts earlier than the axial strain. The long-term strength of the sandstone is determined based on the steady-state creep rate curve, and the value of steady creep rate in the radial direction is slightly less than the axial one, and the long-term strength satisfies a negative exponential relationship with the water content. The ratio of radial strain to axial strain in the creep test is defined as μ_c, μ_c value is independent of water content, and a method for determining the long-term strength of rock based on μ_c value is proposed. For the sandstone samples used in this study, it can be considered that accelerated creep failure will occur in a particular period of time when the ratio surpasses 0.3. As the water content increases, failure pattern of samples gradually change from single inclined plane shear failure to X-shaped conjugate inclined plane shear failure. The research results provide a reliable theoretical basis for long-term stability analysis and early prediction of roadway creep failure under groundwa

Key words: sandstone creep, uniaxial compression creep, water content, radial strain, long-term strength